Hydro-

BHC, benzene bexacbloride, HCH, hexacbloro-cyclobexane, Chlorinated hydro-... 

CH3C(0)CH2Br. Colourless liquid which rapidly becomes violet in colour it is a powerful lachrymator b.p. 1367725 mm. Manufactured by treating aqueous propanone with bromine at 30-40 C it is usual to add sodium chlorate(V) to convert the hydro-bromic acid formed by the reaction back to bromine. It is not very stable and decomposes on standing. 

Process Atmospheric distillation Atmospheric distillation FCC Hydro- cracking Vis- breaking Coking Hydrocracking... 

The pipelines wear and increase of their total length, complex natural-technical and social terms of operation of the most hazardous objects e g., nuclear and heating power plants, chemical and microbiological enterprises, air-space systems, hydro-technical installations, all types of traffic, etc. — here are the reasons of urgent necessity to use as much as possible the NDT and TD systems. 

Many salt-like halides can be prepared by the action of the hydro-halic acid. HX, on the metal or its oxide, hydroxide or carbonate. The halides prepared by this method are often hydrated, particularly when a less electropositive metal is involved, for example zinc, iron. 

Figure 2 76. A typical 2D Molflle of (2R,3f,5P)-2-hydro)cy-3,5-heptadiene nitrile with stereochemical flags (parity values, etc.) in the gray columns. For further explanation, see the text.

O. A. Raevsky, Hydro n Bond Strength Estimation by means of HYBOT. In... 

Meanwhile assemble the apparatus shown in Fig. 62, or that in Fig. 23(D), p. 45, having a distilling-flask of at least 500 ml. capacity in either case. If an ordinary condenser C (Fig. 62) is employed, fit the lower end of the condenser by means of a short piece of rubber tubing to a small inverted funnel. Arrange the latter so that its lip is just below the surface of 25 ml. of concentrated hydrochloric acid diluted with 75 ml. of water contained in a 250 ml. beaker B the hydro-. chloric acid is thereby prevented from being sucked back into the... 

Phenylhydrazine is, however, frequently supplied in the form of its hydro chloride or sulphate, since these salts on exposure to light darken less rapidly than the free base. If these salts are used, however, osazone formation is unsatisfactory, partly because the mineral acid formed by hydrolysis of... 

When diazoaminobenzene is added to a warm aqueous solution of hydrochloric acid, it tends to break up into its original components, i.e., to benzene-diazonium chloride and aniline, and an equilibrium is thus established. The diazonium chloride and the aniline, however, in addition to recombining to form diazoaminobenzene. also undergo direct condensation at the p-hydro-... 

Phenol, 0-, m- and p-cresol, catechol, resorcinol, hydro-quinone (and other nuclear substituted phenols), 1 - and 2-naphthoi... 

Example. Dissolve 0 3 g. of benzoic acid in a minimum of hot water (about 70 ml.) and add 5% aqueous sodium hydro.xide until the solution is just alkaline to methyl-orange, then add i drop of dilute hydrochloric acid. Pour this solution of the sodium salt into a solution of 0 5 g, of benzylthiouronium chloride in 5 ml. of water, and cool the stirred mixture in ice-water. Filter off the benzylthiouronium salt which has separated, and recrystallise from ethanol con taining 10% of water cream-coloured cr> stals, m.p. i66 . (M.ps., pp. 543 545.)... 

Reduction, (a) By sulphurous acid. Benzoquinone, /> toluquinone, 1,2-naphthoquinone are readily reduced by SOj ultimately to the dihydroxy-compound. Thus benzoquinone gives colourless hydro-quinone or quinol, />-C2H4fOH)2. 

TEST Phenol Resorcinol 1 Hydro-Catechol 1 quinone e-Cresol m-C resol p-C resol i-Naphthol 2-Naphthol... 

The Evolution of Methyl Iodide. The flask A (Fig. 89) is now heated with the non-luminous flame of the micro-burner. The immediate result of the heating will be an increase in the rate of bubbles passing up the absorption spiral no endeavour should be made to decrease this flow, however, as it will return to the original rate as soon as the hydro-... 

An important application of the critical solution temperature is to the determination of the water content in such substances as methyl and ethyl alcohols. Here the system is usually the alcohol and a hydro carbon, such as -hexane or dicyclohexyl the water is, of course, insoluble in the hydrocarbon. Thus, the methyl alcohol - cyclohexane system has a C.S.T. of 45 -5° and even 0 01 per cent, of water produces a rise of 0-15° in the C.S.T. The experimental details are given below. 

The so-called hydro-vac pump, shown in Fig. 11, 22, 2 (the upper half of the mercury reservoir and the column above it are insulated by a layer of asbestos), is an inexpensive, all-glass, mercury diffusion pump, which can be used in series either with an oil pmnp or with a water Alter pmnp (compare Fig. 11,21, 1) capable of producing a vacuum of at least 2 mm. It is accordingly of particular value in the organic laboratory for vacuum distillations, fractionations, sublimations and pyrolyses as well as for molecular distillations (see Section 11,26). The hydro-vac... 

About 150 ml. of concentrated sulphuric acid is placed in the larger funnel and 100 ml. of concentrated hydrochloric acid in the smaller separatory funnel. The latter is raised until the capillary tube is above the sulphuric acid, the capillary tube is filled with concentrated hydrochloric acid, and the stopper replaced. The rate of evolution of hydrogen chloride is controlled by regulation of the supply of hydro chloric acid this will continue until a volume of hydrochloric acid equal to that of the concentrated sulphuric acid has been used. The diluted sulphuric acid should then be removed and the apparatus recharged. The yield is 31-33 g. of hydrogen chloride per 100 ml. of concentrated hydro chloric acid. If more than an equal volume of hydrochloric acid is employed, the yield of gas decreases and continues to be formed for a tune after the stopcock has been closed. 

Semi- carbazone Oxime Hydro- quinone DIacetate of hydro-quinone Thiele acetylation product Other Derivatives... 

Hydrolysis may be effected with 10-20 per cent, sodium hydroxide solution (see p-Tolunitrile and Benzonitrile in Section IV,66) or with 10 per cent, methyl alcoholic sodium hydroxide. For diflScult cases, e.g., a.-Naphthoniirile (Section IV,163), a mixture of 50 per cent, sulphuric acid and glacial acetic acid may be used. In alkahne hydrolysis the boiling is continued until no more ammonia is evolved. In acid hydro-lysis 2-3 hours boiling is usually sufficient the reaction product is poured into water, and the organic acid is separated from any unchanged nitrile or from amide by means of sodium carbonate solution. The resulting acid is identified as detailed in Section IV,175. 

Cool the flask in ice, acidify with 10 ml. of cold 1 1-hydro-chloric acid and distil under reduced pressure (water pump) until most of the alcohol is removed. Add water to the residue, extract several times with ether, wash the combined ethereal extracts with N ammonia solution until a test portion gives no precipitate upon acidification. Extract the combined alkahne solutions once with a fresh portion of ether, and add the aqueous solution to an excess of dilute hydrochloric acid the final mixture should still be acidic to Congo red. Collect the crystalhne half-ester by filtration at the pump, wash it with water and dry at 100°. The yield is 14-5 g., m.p. 122-125°. Recrystallise by dissolving in about 40 ml. of warm benzene and adding an equal volume of petroleum ether (b.p. 40- 60°) 13 -5 g. of the colourless half-ester, m.p. 125-126°, are obtained. 

Place 25 g. of methyl methacrylate polymer (G.B. Diakon (powder). Perspex (sheet) U.S.A. Lucite, Plexiglass) in a 100 ml. Claisen flask, attach an efficient condenser e.g., of the double smface type) and distil with a small luminous flame move the flame to and fro around the sides of the flask. At about 300° the polymer softens and undergoes rapid depolymerisation to the monomer, methyl methacrylate, which distils over into the receiver. Continue the distillation until only a small black residue (3-4 g.) remains. Redistil the hquid it passes over at 100-110°, mainly at 100-102°. The yield of methyl methacrylate (monomer) is 20 g. If the monomer is to be kept for any period, add 0 -1 g. of hydro quinone to act as a stabiUser or inhibitor of polymerisation. 

It may be noted that primary aliphatic amides are readily converted by hydro-xylamlne hydrochloride into hydroxamic acids, which may be detected by the addition of ferric chloride solution ... 

Sulphoxides. These are usually solids of low m.p. They may be oxidised in glacial acetic acid solution by potassium permanganate to the corresponding sulphones, and reduced to the sulphides by boiling with tin or zinc and hydro chloric acid. 

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